Mark Everett Sloan, M.D., F.A.C.S. is a fictional character from ABC's medical drama television series Grey's Anatomy, portrayed by #EricDane. Created by showrunner Shonda Rhimes, the character was introduced in season two as Derek Shepherd's best friend who caused the end of Shepherd's marriage by sleeping with his then-wife, Addison Montgomery. He moves to Seattle in season three to make amends with Derek and becomes Seattle Grace Hospital's new plastics attending, after which he is dubbed “McSteamy” by the female interns for his good looks.